當UITextField已滿或爲空時顯示警報Swift

Question

以下代碼表示如果userNameTF或passwordTF已滿或爲空，它將顯示警報。

@IBAction func LoginBtn(sender: AnyObject) { 
    let userName = userNameTF.text 
    let password = passwordTF.text  

    if ((userName?.isEmpty) != nil) { 

     displayMyAlertMessage ("Forget to fill your user name") 
     return   
    } 

    if ((password?.isEmpty) != nil){ 

     displayMyAlertMessage ("Forget to fill your password") 
     return  
    }   
} 

func displayMyAlertMessage(userMessage:String){ 

    let myAlert = UIAlertController(title: "WOF", message: userMessage, preferredStyle: UIAlertControllerStyle.Alert) 
    let okAction = UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: nil) 
    myAlert.addAction(okAction) 
    self.presentViewController(myAlert, animated: true, completion: nil) 
} 

Answer 1

這是使用guard

@IBAction func LoginBtn(sender: AnyObject) { 

    guard let userName = userNameTF.text where !userName.isEmpty else { 
     displayMyAlertMessage ("Forget to fill your user name") 
     return 
    } 

    guard let password = passwordTF.text where !password.isEmpty else { 
     displayMyAlertMessage ("Forget to fill your password") 
     return 
    } 

    // do something with userName and password 
} 

Answer 2

你可以用我的代碼簡單地檢查你的代碼。你做的檢查值是否有空有小錯誤。

按照下列步驟進行：

1）定義爲IBOutlet中文本框

@IBOutlet var userNameTF : UITextField! 
@IBOutlet var passwordTF : UITextField! 

2.）寫在下面的代碼上按鈕點擊事件。

let userName = userNameTF.text 
    let password = passwordTF.text 

    if (userName!.isEmpty) 
    { 
     displayMyAlertMessage ("Forget to fill your user name") 
     return 
    } 
    else if (password!.isEmpty) 
    { 
     displayMyAlertMessage ("Forget to fill your password") 
     return 
    } 
    else 
    { 
     // Do Whatever u want. 
    } 

享受編碼...它的工作很好。